Ski boot



- Sept. 29., 1970 R. w. vcGEL 3,530,594

SKI BOOT l Filed Sept. 6, 1967 5 Sheets-Shoot 1 y ,Sept 29 1970 l R. w. voc-:.El. 3,530,594

SKI BOOT Fned'sept. e, 1967 s sheets-sheet a SPf 29 1970 l R. w. VOGEL 3,530,594

, SKI BOOT Filed Sept. 6, 1967 Y 5 Sheets-Sheet 5 FIG. 3

3 l 5 fa? 27 3 ZIT ZIQ` R. W. VOGEL scpc. 2a, 1970 SKI BOOT 5 Sheets-Sheet L Filed Sept. 6, 1967 Filed sept. e, 19ev` Sept. 29, 1970 w. VOGEL 9 3,530,594

sx1 BooT 5 Sheets-Sheet 5 Ffa? United States Patent O m 3,530,594 SKI BOOT Raimund W. Vogel, Lierstrasse 2S, Munich, Germany Continuation-impart of application Ser. No. 541,896, Mar. 18, 1966. This application Sept. 6, 1967, Ser. No. 683,746

Int. Cl. A43b U.S. Cl. 36--25 12 Claims ABSTRACT OF THE DISCLOSURE A ski boot whose foot portion includes a grid-upwardly open shell which receives and supports the foot and is a unitary piece of rigid plastic. A foil of thin and pliable plastic or leather closes the open top of the shell and extends to the shaft portion which may include a forwardly open upper stiff cuff, rigid in normally vertical planes but sufciently flexible in a horizontal plane to be bent apart for insertion of the heel of the foot into the boot. The cuff is hingedly fastened to the foot portion and guided so that it can pivot only in a plane longitudinal of the boot.

CROSS-REFERENCE TO RELATED APPLICATION This application is a continuation-in-part of my copending application Ser. No. 541,896, filed on Mar. 18, 1966 now Pat. No. 3,410,006.

BACKGROUND OF THE INVENTION This invention relates to footwear, and particularly to a ski boot mainly consisting of rigid synthetic resin composition of plastic.

The advantages of plastic ski boots have been obvious for some time. They are readily made waterproof, and they indefinitely resist the deterioration by water to which leather boots are subject. Many plastics are highly resistant to abrasion and cutting by granular snow at low temperature and by the steel edges of the skis. At equal mechanical strength, plastics are lighter and much cheaper than leather.

Yet, the design of plastic ski boots presents problems which were not solved heretofore. The plastic boot must be quite stiff if it is to transmit movements of the foot and leg to the ski with the precision required in modern skiing techniques. The wall thicknesses heretofore considered necessary for adequate rigidity make the known plastic boots rather heavy and bulky. In order to permit insertion of the foot into the boot, a normally closed entrance opening has to be provided in the stiff structure, and it was necessary hingedly to remove parts of the shoe or to use similar expedients which further increase the weight, bulk, and cost of the boot.

Another important problem not adequately solved by the known boots resides in the proper compromise between ski control and wearers comfort. If the foot is loosely held in the boot, control motions of the foot and leg are transmitted by the boot to the ski with a signicant delay and with some lost motion. If the known boots engage the foot firmly enough for good ski control, only a limited number of persons can tolerate the necessary pressure, particularly on the sensitive top surface of the foot.

It is the primary object of this invention to provide a plastic ski boot which avoids the aforementioned and other shortcomings of the known boots, and which provides full control of ski movements without discomfort to the wearer.

SUMMARY OF THE INVENTION lt has been found that the weight and bulk of a ski boot can be held to a minimum by the judicious selection and arrangement of the materials of construction for the Patented Sept. 29, 1970 several parts of the boot, and that a plastic ski boot can be comfortable to wear while adequately rigid by avoiding the transmission of pressure from the boot to the most sensitive parts of the foot, and the concentration of any transmitted pressure on small areas of the foot.

In one of its basic aspects, this invention provides a boot with an elongated unitary shell of substantially rigid synthetic resin composition which envelops the foot by side walls, a bottom wall, and rear walls, but whose cavity, as defined by these walls, has a side which is open in a direction away from the bottom wall carrying an outsole.

The cavity is sealed about the inserted foot and the ankle of a wearer by a foil of a material much less rigid than the shell. Two portions of the foil are sealingly and fixedly attached to the two side walls of the shell and cover respective portions of the open cavity side.

Preferably the side and rear walls of the shell are reinforced by elements preferentially elongated in a direction to impart to these walls substantially greater resistance against bending in all planes perpendicular to the bottom wall than in planes parallel to the bottom wall. lf the boot is also provided with an upper shaft member of rigid plastic or synthetic resin composition, it may be similarly reinforced.

The upper shaft member has lateral and rear portions which respectively extend upward from the side walls and the rear wall of the shell in the normal operating position of the boot. At least one side wall of the shell is hingedly connected in the region of the ankle to the corresponding lateral portion of the upper shaft member, while cooperating guide elements on the rear wall of the shell and the rear portion of the upper shaft member confine hinged movement of the shell and the upper shaft member to one plane `which is longitudinal of the boot and transverse of the bottom wall of the shell.

Other features, additional objects, and many of the attendant advantages of this invention will readily 1be appreciated as the same becomes better understood by reference to the following detailed description of preferred embodiments when considered in connection with the attached drawing.

BRIEF DESCRIPTION OF THE DRAWING In the drawing:

FIG. 1 shows a ski boot of the invention in cross section in the region of the ball.

FIG. 2 shows a portion of the boot of FIG. l on a larger scale in the region of line Il.

FIG. 3 shows the boot in side elevational section on its median plane.

FIG. 4 illustrates the view in perspective of two stiifening parts of plastic of a ski boot hingedly connected.

FIG. 5 is a perspectively enlarged view of a ski boot in two parts, hingedly connected with a cuff overlapping in the region of the heel.

FIG. 6 shows a security hinge with notches of the axis.

FIG. 7 shows hinge tapes.

FIG. 8 shows divided sealing tapes with security look in perspective.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to the drawing in detail, and initially to FIGS. l to 3, there is seen a ski boot of the invention which includes a rigid shell 1 of reinforced epoxy resin composition. The shell has a bottom wall which is represented by horizontal reinforcing layers 10 which is integral with two longitudinal side walls which are represented mainly by reinforcing layers 11 and 12 in its portion away from the bottom wall. The shell encloses an upwardly open cavity shaped to receive the foot of a 3 wearer with suiiicient clearance to provide space for a layer of rigid, open-celled urethane foam which covers the internal surfaces of the bottom and side walls 10, 11 and 12 and also extends along the rear wall and the toe box. An outsole 2 of rubber is attached to the bottom wall outside the cavity.

As is best seen in FIG. 2 the side Walls 11 and 12 in its vertical portion of the shell 1 is reinforced with two layers of fabrics 12 which extends into the bottom wall, and the latter has four additional reinforcing fabric layers 10 parallel and above the outsole 2. The fabrics 10 and 12 consist of glass iibers in a warp:weft relation of 2:0.9/ centimeter (cm.), warp=glass roving, weft=spun glass thread number metric 3, tensile strength of the warp=180 kg./cm. and of the weft=3 kg./cm. The Warp threads of the layers 10 extend longitudinal to the length of the boot and the warp threads of the layer 12 extend lateral to the length of the boot, so that the side wall is less rigid in a longitudinal plane than in an upright transverse plane. In the bottom wall the warp threads of 10 and 12 are crossing to make the sole practically iniiexible under normal operating stresses. A wedge-shaped portion 13 of the shell 1 between the fabric layers 11, 10 at the junction of the side wall and bottom wall does not require special reinforcements. The reinforcing fabric 11 is described later. The weight ratio epoxy resin:glass fiber is 30:70.

Respective portions of a pliable polyurethane foil 4 are fixedly attached to the two side walls by cementing or otherwise. The foil 4 which extends in FIG. l only left from the sole 2 upward beyond the top edges 3 of the side walls closes the open top of the shell 1 and also constitutes the shaft of the boot. A felt lining 8 covers a foam plastic layer 7 and all other internal surfaces of the boot to provide additional cushioning and to improve ventilation of the boot cavity.

Circulation of air through the communicating cells in the layer 7 and within the cavity of the shell 1 is enhanced by a simple pumping arrangement consisting essentially of a body of open-celled foam plastic which fills a recess 14 in a urethane foam layer 7 under the heel of the wearer. During normal walking or skiing, the body 15 is alternatingly compressed and permitted to expand by the weight of the wearer as the weight is shifted from one foot to the other and between the heel and the metatarsal portion of the wearers foot. It will be appreciated that the elastic modulus of the body 15 is much smaller than that of the surrounding portions of the layer 7.

A strong, but pliable nylon band 5 is fastened in the side walls of the shell 1 and the foil 4 in the metatarsal portion of the boot. The foil 4 is partly split approximately along the longitudinal median plane of the boot. When the buckles 5 on the ends of the two bands 5 are engaged, and the bands are tightened, the free edges of the foil portions overlap to seal the foot of the wearer in the cavity of the shell 1.

The side walls decrease in thickness in an upward direction toward the edges 3 so that the upper edge portions are not quite as rigid as the portions nearer the bottom wall. As is seen in FIG. 3, each edge portion has vertical slots 21 on each side of the tape 5, and the tong of shell material between the slots tends to bend inward of the cavity when the bands 5 are tightened, whereby the shell is drawn toward the foot of a wearer on either side, and the foot is firmly held against the bottom wall without pressure against the sensitive top surface of the foot.

A band provided with a buckle 20 is similarly arranged nearer the rear wall of the shell 1. The central portion of the band 20 is molded into the side walls of shell 1, and the two ends extend obliquely upward and forward along the outer faces of the side walls and under the foil 4. The buckle 20', as well as the buckle 5 are fastened to the associated bands 5, 20 by rivets (not shown) which pass through the foil 4. Slots corresponding to the slots 21 may be provided near the band 20, but have been found to be not quite as important for the comfort of the wearer as the slots near the metatarsal bands 5.

The bands 5, 20 are preferably provided with a release mechanism of the type described hereinafter with reference to FIG. 8, but omitted from the showing of FIGS. l to 3 for the sake of clarity. The shell 1 is reinforced at the upper outside level of the bottom Wall and on the side walls by fabrics 11 of about 1.05 mm. thickness and in sections in the direction of the desired greatest stiffness or elasticity in the side wall. This fabric consists in section 16 (FIG. 3) of l mm. thick spring-steel-wires (elasticity modulus (EM) of 2 million kg./cm.2 and a tensile strength (TS) of 200,000 kg./cm.2), 7 wires per cm., in section 17 of glass rovings with sixty threads (EM 700,000, TS 14,000), 6 rovings per cm. and in section 18 of l mm. polyamide threads (EM 1,000, TS 6,000), 7 threads per cm., as warp parallel next to each other and running from the upper edge 3 of the side wall over the bottom wall to the upper edge 3 of the opposite side wall. Across to the warp in the weft are glass rovings with thirty threads, 2 for cach cm. The point of the boot 19 has a wall thickness of four mm. and consists of 50:50 per Weight epoxy resin to cut glass fibers. Section 17 is more elastic than section 16 and section 18 is still more elastic. This differentiated way of reinforcement makes the boot stiffer (at the heel section) where it is necessary from the point of view of the skiing technique and more elastic where it is desirable, physiologically for the foot (section of the ball). This boot is in spite of thin walls and lightness very strong.

The boot shown in FIG. 1 on the right outer side has at least partly a layer 9 of abrasion resistant material (Le. epoxy resin EM 1,000 added 30% of silicium carbide). This layer is suitable for any boot. FIG. 4 shows a stiiiening part for ski boots, consisting of a lower and an upper part connected by hinge 32 on one side and a guiding mean 35 in the rear, the latter is fixed in one part and slidable in the other. Hinge 32 consists of two steel bands 33, 34 fixed to the upper 31 and lower part 30. The guiding mean 35 slides in a sheath 36. The upper part 31 surrounds the shank on the sides and the rear above the ankles cufllike, being open in the front. By the double hinged combination of the stiffening parts 30, 31 the latter can be light remaining in position laterally. This stiffening set up may be used for any ski boot.

The modified ski boot in FIGS. 5 to 8 has a shell 1 similar to the shell 1 of FIGS. 1 to 3 except for a reinforcing molded sheet metal insert 43 which envelopes the sides and bottom of the wearers heel and is embedded in the resin base of the shell 1. The open top of the cavity in the shell 1 is partly closed by a slotted foil 4 which extends over the front part of the foot and over the frontal aspect of the shaft. It is dealed in the operating condition of the boot by a closure arrangement including metatarsal bands 5 and a buckle 5 as well as `by an instep band 20 and an associated buckle 20" in the manner described with reference to FIG. 3. The interior of the shell 1 is lined with cellular material and felt as shown in FIGS. 1 to 3.

The shaft of the modified boot is mainly formed by a cuff 40 of epoxy resin sheet reinforced with glass fibers which mainly extend in a normally vertical direction so that the cuff is less rigid in a horizontal plane than in any vertical plane. It is U-shaped in horizontal section, and its open front is normally closed by the foil 4 Whose parts are sealed to the two lateral portions of the cuff 40 when a band 46 attached to the lateral cuff portions is closed and tightened by a buckle 46 near the top of the cuff 40, an end of the band 46 being held between the cuff 40 and the internally attached foil 4 in a manner analogous to the anchoring of the bands 5, 20 described above.

The lower end of the cuff is attached to the side walls of the shell 1 by two hinges 42, 44 on respective vertically elongated metal strips embedded in the cuff 40 on either side of the wearers ankle. Each hinge 42, 44 includes an internally bushing iixedly fastened in the aforementioned sheet metal insert 43, 51, as is best seen in FIG. 6. A portion of the bushing is rotatably and axially slidably received in a bore of the associated metal strip 45, and axial release of the bushing from the strip 45 is normally prevented by abutting engagement of the strip with the head 54 of a bolt 53 threadedly received in the bushing 52. Annular notches 56 extending in the head 54 near the stem of the screw cause the head to break from the stem under severe axial stresses, thereby axially releasing the bushing from engagement with the strip 45.

The strip 45 and the portion of the insert 43 receiving the bushing 50 are mounted directly under the surface of the associated stl plastic members 40', 1, but are retained safely in the plastic members in the manner shown with reference to the strip 45 in FIG. 7. The face 61 of the strip 45 is narrower than the embedded other face to which it is parallel. The narrow side faces 62 of the strip thus approach each other in a direction from the wide to the narrow parallel face. The anchorage provided to the strip 45 by the illustrated configuration of the narrow side faces 62 is stronger than the frangible attachment of the head 54 to the stem of the screw 53.

The angular movement of the cuif 40 on the shell 1 is additionally guided in a plane longitudinal of the boot and perpendicular to the boot sole by a resilient guide blade or bar 35 attached to the rear wall of the cuff 40 and slidable in the corresponding portion of the shell 1 in an upright position. The blade 35 is received in a bearing channel 36 molded into the shell 1 for longitudinal sliding motion.

Moreover, the rear bottom portion 41 of the cuff 40 and the top portion of the rear wall on the shell 1 are of circularly arcuate section about the common axis of the 'hinges 42, 44 and the inner face of the cuff portion guidingly cooperates including said axis overlapping the outer face on the shell rear wall to prevent torsional deformation of the cuff 40H. The guidance provided by the blade 35 and the channel 36 is normally suflicient for proper functioning of the boot if at least one hinge 42 or 44 is intact. The advantage of the boot with a cuif 40 which is hinged to the shell 1 consists by combination if the hinges 42, 44 with the circularly arcuate sections 41 of parts 1, 40 are guidingly cooperating.

The rigid, upwardly open unitary shell 1 is made by a technique press process. Glass fiber fabric is cut to the necessary shape, impregnated with catalyzed epoxy resin composition, and then put together with the tapes 5, 20 in a mold which also carries the metallic inserts. Several layers of impregnated fabric are superimposed as is partly indicated in FIG. 2 which shows several layers by way of example only. Commercially available fabrics consisting of strands of glass fibers (rovings) have been found advantageous, but the invention is not limited to specific known reinforcing elements. Metal wires preferentially elongated in the direction in which maximum rigidity is desired have been used successfully, and textile fibers, for example polyamide iibers, may be employed where maximum rigidity is not called for. Plastics other than the specifically disclosed epoxy resin compositions will readily suggest themselves for construction of the rigid boot shells or culfs. Stiff thermoplastic resins are also suitable for the rigid parts of the boot.

The shells, because of their open tops, may be bound tightly to the foot by the metatarsal and instep bands without causing discomfort to the wearer. Tight conforming engagement between the boot and the foot is necessary for precise transmission of foot and leg movements to a ski 6 attached to the boot without delay and without lost motion. The light and thin foil 4 of plastic or thin, pliable leather seal the boot without exerting noticeable pressure on the foot even when creased and folded as during skiing with bent knees. They need not be provided with longitudinal slots if so desired. The toe box need not be integral with the shell 1.

rl`he side walls of the boot must be rigid against flexing transversely of the direction of boot elongation, and their rigidity in other directions is not important. By placing glass fibers mostly in a normally vertical position in the side walls, the necessary rigidity is achieved at the lowest possible weight and thickness of the boot, the weight and bulk thereof being inversely related to the wearers comfort.

Similarly, the cuff 40` which forms much of the shaft in the boot of FIG. 5 needs to be stiff only in normally vertical planes. Unnecessary weight and bulk would be added to the boot if it were equally reinforced against ilexure in horizontal planes. A boot of the invention provided with a plastic cuff is easily pulled over the foot or taken off when the front edges of the lateral cuff portions are resiliently spread apart. Yet, when the cuff is tightened about the wearers ankle, relative torsional movement of boot and leg about a vertical axis under normal skiing stresses is virtually impossible. The cuff can tilt only forward and backward through an angle. Movements of the lower leg are transmitted by the boot of the invention to an attached ski 6 with surprisingly little effort on the part of the skier.

The boots when equipped with the release mechanism 69 shown in detail in FIG. 8 avoid injuries to the Skier when his safety bindings fail to release the boot from the skis. The bands 5, 20, 46 can be adjusted by merely turning the clamping screw 73. The tension at which the band parts 5, 20, 46 are permitted to separate, thereby releasing the foot from the boot, may be set fairly by means of a screw driver equipped with a torque gage, but with little experience the gage is unnecessary. The release mechanism 69 is situated between the attachment of the bands 5, 20, 46 in the stiff parts 1, 40' and the buckles 5', 20', 46. This release mechanism can be used in any ski boot.

The boot of FIGS. 5 to 8 additionally releases the foot of a wearer under stresses suflicient to break the heads 54 from the screws 53 at the annular grooves 56 in the hinge pin arrangements as described before.

The material for the open-celled foam lining 7 must be carefully selected to provide a limited cushioning effect for the wearers comfort without unduly loosening the grip of the boot on the foot and leg. Extended experiments have shown a rigid open-celled foam material with a compression strength of 0.2 to 50 kg. per cm.2, and its elasticity should be such that its thickness is not reduced by more than 30%. A compression strength of about l kg./cm.2 gives good and economical results under most conditions and an elasticity of about 5 to 15% is normally tolerable for precise ski control while providing adequate comfort.

Urethane foams satisfying these requirements are now commercially available at low cost, but other open-celled plastics are equally useful. A foam plastic lining satisfying the mechanical requirements outlined above has the advantage of being permanently deformed locally under loads greater than the general weight of the wearer, yet easily provided manually or with simple tools. The internal contour of the boot may thus be adjusted permanently to specific features of the foot by locally applied pressure of the bones of the foot strong enough to break the cell walls of the rigid foam. The foam lining is suitable for any ski boot to cover completely or partly the cavity of the boot.

It Should be understood, of course, that this disclosure relates only to preferred embodiments of the invention, and that it is intended to cover all changes and modifications of the examples of the invention which do not 7 constitute departures from the scope and spirit of the invention set forth in the appended claims.

What is claimed is:

1. A ski boot comprising, in combination:

(a) an elongated, unitary shell member of substantially rigid synthetic resin composition having a substantially U-shaped cross-section,

(1) said shell member having a longitudinal bottom wall, two longitudinal side walls, and a rear wall transverse to the bottom and side walls,

(2) said walls jointly dening an elongated cavity having a side open in a direction away from said bottom wall;

(b) sealing means for sealing said cavity about the foot and the ankle of a wearer when said foot is inserted in said cavity,

(l) said sealing means having a foil portion which is divided at a rear boot part, overlaps and is of a material less rigid than said composition;

(2) said foil portions being sealingly and fixedly attached to said side walls respectively and covering respective portions of the open side of said cavity; and

(c) an outsole fixedly fastened to said bottom wall outside said cavity.

2, A boot as set forth in claim 1, wherein said composition in said side and rear walls includes reinforcing means preferentially elongated in a direction for imparting to said side and rear walls substantially greater resistance against bending in all planes perpendicular to said bottom Wall than in planes parallel to said bottom wall.

3. A boot as set forth in claim 1, wherein said sealing `means further include a shaft member of substantially rigid sheet material substantially consisting of a synthetic resin composition, said shaft member having two lateral portions extending upward from said side walls respectively, and a rear portion extending upward from said rear wall, hinge means connecting one of said side walls to the corresponding lateral portion for arcuate movement of said members relative to each other in a plane longitudinal of said shell member and transverse of said bottom wall, and cooperating guide means on said rear wall and on said rear portions confining said movement to said longitudinal plane.

4. A boot as set forth in claim 3, wherein said sheet material includes reinforcing means for imparting to said shaft member substantially greater resistance against bending in planes perpendicular to said bottom wall than in planes parallel to said bottom wall.

5. A boot as set forth in claim 3 wherein said guide means include a resilient guide bar attached to one of said members and a bearing on the other member slidably receiving said guide bar.

6. A boot as set forth in claim 3 wherein said hinge means include pivot pin means having an axis and being received in one of said members for angular movement about said axis and for axial sliding movement, and head means frangibly secured to said pin means for preventing axial movement of said pin means out of receiving engagement with said one member.

7. A boot as set forth in claim 1, further comprising transverse instep band means for connecting respective opposite portions of said side Walls remote from said bottom wall, said instep band means including a pliable band member having one end portion attached to one said side wall portions and closure means for releasably connecting the other end portion of said band member to the other side wall, said portions of said side walls being nearer said rear wall than the forward end of said shell member, the boot further comprising transverse material band means spacedly interposed between said instep band means and said forward end for releasably connecting said side walls.

8. A boot as set forth in claim 7 wherein said side walls have respective longitudinal edge portions remote from said bottom wall, one of said edge portions being formed with a transverse slot on each side of one of said band means.

9. A boot as set forth in claim 7 wherein said band member is elongated and has two longitudinal parts, the instep band means further including linking means normally attaching said parts to each other, but responsive to a predetermined tension in said parts to permit separation of said parts, said linking means including means for adjusting said tension.

10. A ski boot substantially of plastic material comprising within the boot a layer of cellular material covering the cavity which is built by the outside 'material of the boot, substantially all cells of the cellular material communicating with each other and with said cavity, said cellular material having a compression strength of 0.2 to 50 kg./cm.2, and being reduced in thickness by not more than 30 percent when stressed in the direction of the thickness thereof.

11. A boot as set forth in claim 10 wherein said layer is formed with an opening therein, and a body of opencelled, elastic cellular material received in said opening, the modulus of elasticity of said body in compression being substantially smaller than the corresponding modulus of said layer.

12. A boot as set forth in claim 3 wherein said resin composition includes a reinforcing metal insert member having two opposite and substantially parallel faces of different width, and two side faces connecting said parallel faces and approaching each other from the wider toward the narrower parallel face, said narrower face being nearer the nearest surface of said shell member than the wider face is from a corresponding surface of the shell member.

References Cited UNITED STATES PATENTS 3,374,561 3/1968 Werner et al. 36-2.5 3,407,406 10/1968 Werner et al. 36-2.5X

FOREIGN PATENTS 1,193,946 11/1959 France.

PATRICK D. LAWSON, Primary Examiner 

